Process and apparatus for registering a continuously moving, treatable layer with another

ABSTRACT

A process and apparatus for controllably registering two continuously moving layers of material is provided. One of the layers comprises a permanently settable material, and has a plurality of reference marks representing a plurality of separate and distinct components, and the other of the continuously moving layers has a respective plurality of different components thereon. The process and apparatus controls the distance between reference marks to a selected distance, and controllably registers each reference mark to a respective component of the continuously moving second layer.

BACKGROUND OF THE INVENTION

The present invention generally relates to processes and apparatus formaking disposable absorbent articles, and particularly to processes andapparatus for making disposable absorbent articles having registeredcomponents.

Various products are fabricated in a continuous production line by thesequential addition of components to previously supplied components.This is particularly advantageous when one or more of the components canbe supplied in the form of a single continuous layer. For example, inthe formation of disposable absorbent articles, such as training pants,diapers, incontinence articles, feminine care products, or the like, alayer is normally supplied at a point in the fabrication line in theform of a continuous roll, and absorbent pads, waist elastic bands, legelastic bands, stretchable side panels, and/or other elements orcomponents can be supplied at different points in the fabrication lineas discrete objects.

Various methods and apparatus are available for bringing the componentsof a single product together so that the components in the compositeproduct are in a desired relation with respect to each other. Inbringing these components properly together, various known methods andapparatus are used to note the position of a particular component, andthen to adjust the position of subsequent components in order toproperly position them.

A problem encountered with these types of methods and apparatus is thatthey do not adequately compensate for the stretching or relaxing of acontinuously moving layer. During manufacturing processes of this type,a continuously moving layer is subjected to various tensions caused byit being driven or pulled through the process for handling. This tensioncauses the continuously moving layer to stretch, or to relax, therebyresulting in some components being undesirably positioned or, oncepositioned, shifted out of position. Since it is virtually impossible tomaintain a constant tension on the continuously moving layer, the degreeof stretching varies throughout the process. Consequently, even thoughan earlier positioned component may initially be within an acceptableposition range, the stretching or relaxing of the continuously movinglayer may result in the component being outside of the acceptableposition range in the final composite product.

Another problem with current methods and apparatus is that they do notprovide an adequate means for registering two continuously movinglayers, and particularly when one of the layers has a pre-printed orpre-positioned component or the like that is to be registered with apre-printed or pre-positioned component or the like on the other of thelayers during the manufacture of a plurality of products having adesired registration of components.

SUMMARY OF THE INVENTION

In response to the discussed difficulties and problems encountered inthe prior art, the present invention provides a process and apparatusfor registering a plurality of components on one continuously movinglayer with a respective plurality of components on a continuously movingsecond layer comprising a permanently settable material.

In one form of the present invention there is provided a process forcontrollably registering a plurality of components of a continuouslymoving first layer with a plurality of components on a continuouslymoving second layer, comprising the steps of: (1) providing acontinuously moving first layer including a plurality of componentsbeing spaced apart a selected length, (2) providing a continuouslymoving second layer comprising a permanently settable material, andincluding a plurality of components being spaced apart a length lessthan the selected length, (3) representing the components of thecontinuously moving second layer with a respective plurality ofreference marks, (4) sensing each of the reference marks and generatinga reference mark signal in response thereto, (5) measuring the distancebetween two successive reference mark signals and generating a repeatcorrective control signal in accordance with preprogrammed instructions,(6) drawing the continuously moving second layer to adjust the distancebetween two successive reference marks in response to a generated repeatcorrective control signal, (7) superimposing the continuously movingfirst layer and the continuously moving second layer together, (8)sensing a reference mark of the continuously moving second layer and itscorresponding component of the continuously moving first layer, andgenerating a placement corrective control signal in accordance withpreprogrammed instructions, and (9) adjusting the speed of thecontinuously moving second layer in response to a generated placementcorrective control signal to controllably register a reference mark onthe continuously moving second layer with its corresponding component onthe continuously moving first layer.

In another form of the present invention there is provided a process forcontrollably registering a plurality of reference marks of acontinuously moving first layer with a plurality of correspondingreference marks of a continuously moving second layer, comprising thesteps of: (1) providing a continuously moving first layer including aplurality of reference marks being spaced apart a selected length, (2)providing a continuously moving second layer comprising a permanentlysettable material, and including a plurality of corresponding referencemarks being spaced apart a length less than the selected length, (3)sensing each of the reference marks of the continuously moving secondlayer and generating a reference mark signal in response thereto, (4)measuring the distance between two successive reference mark signals andgenerating a repeat corrective control signal in accordance withpreprogrammed instructions, (5) drawing the continuously moving secondlayer to adjust the length in response to a generated repeat correctivecontrol signal, (6) superimposing the continuously moving first layerand second layer together, (7) sensing a reference mark of thecontinuously moving second layer and its corresponding reference mark ofthe continuously moving first layer and generating a placementcorrective control signal in accordance with preprogrammed instructions,and (8) adjusting the speed of the continuously moving second layer inresponse to a generated placement corrective control signal tocontrollably register a reference mark of the continuously moving secondlayer with its corresponding reference mark on the continuously movingfirst layer.

In yet another form of the present invention there is provided anapparatus for controllably registering a plurality of components of acontinuously moving first layer with a plurality of components on acontinuously moving second layer, comprising: (1) means for providing acontinuously moving first layer including a plurality of componentsbeing spaced apart a selected length, (2) means for providing acontinuously moving second layer comprising a permanently settablematerial, and including a plurality of components being represented witha respective plurality of reference marks being spaced apart a lengthless than the selected length, (3) means for sensing each of thereference marks and means for generating a reference mark signal inresponse thereto, (4) means for measuring the distance between twosuccessive reference mark signals and means for generating a repeatcorrective control signal in accordance with preprogrammed instructions,(5) means for drawing the continuously moving second layer to adjust thedistance between two successive reference marks in response to agenerated repeat corrective control signal, (6) means for superimposingthe continuously moving first layer and the continuously moving secondlayer together, (7) means for sensing a reference mark of thecontinuously moving second layer and its corresponding component of thecontinuously moving first layer, and means for generating a placementcorrective control signal in accordance with preprogrammed instructions,and (8) means for adjusting the speed of the continuously moving secondlayer in response to a generated placement corrective control signal tocontrollably register a reference mark on the continuously moving secondlayer with its corresponding component on the continuously moving firstlayer.

In still yet another form of the present invention there is provided anapparatus for controllably registering a plurality of reference marks ofa continuously moving first layer with a plurality of correspondingreference marks of a continuously moving second layer, comprising: (1)means for providing a continuously moving first layer including aplurality of reference marks being spaced apart a selected distance, (2)means for providing a continuously moving second layer comprising apermanently settable material, and including a plurality ofcorresponding reference marks being spaced apart a length less than theselected length, (3) means for sensing each of the reference marks ofthe continuously moving second layer and means for generating areference mark signal in response thereto, (4) means for measuring thedistance between two successive reference mark signals and means forgenerating a repeat corrective control signal in accordance withpreprogrammed instructions, (5) means for drawing the continuouslymoving second layer to adjust the length in response to a generatedrepeat corrective control signal, (6) means for superimposing thecontinuously moving first layer and second layer together, (7) means forsensing a reference mark of the continuously moving second layer and itscorresponding reference mark of the continuously moving first layer andmeans for generating a placement corrective control signal in accordancewith preprogrammed instructions, and (8) means for adjusting the speedof the continuously moving second layer in response to a generatedplacement corrective control signal to controllably register a referencemark of the continuously moving second layer with its correspondingreference mark on the continuously moving first layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features of the present invention and themanner of attaining them will become more apparent, and the inventionitself will be better understood by reference to the followingdescription of the invention, taken in conjunction with the accompanyingdrawings wherein:

FIG. 1 illustrates a front view of one article having a registeredgraphic thereon;

FIG. 2 illustrates a front view of another article having a registeredgraphic thereon;

FIG. 2A representatively illustrates the article of FIG. 2 in apartially disassembled, stretched flat state;

FIG. 3 illustrates a continuously moving layer having a plurality ofseparate and distinct graphics thereon;

FIG. 4 illustrates a continuously moving composite layer having aplurality of separate and distinct graphics thereon;

FIG. 5 schematically illustrates an apparatus and process for themanufacture of an article having a registered graphic thereon;

FIG. 6 illustrates a schematic block diagram of the flow of datautilized in conjunction with the apparatus and process in FIG. 5;

FIG. 7 illustrates a block diagram of the electronic gear box in FIG. 6;and

FIG. 8 graphically illustrates a placement control utilized inconjunction with the apparatus and process in FIG. 5.

DETAILED DESCRIPTION

The following detailed description will be made in the context ofregistering and controlling the registration of at least onecontinuously moving layer with respect to at least a second continuouslymoving layer in the manufacture of disposable absorbent articles, andspecifically a child's disposable absorbent training pant. Examples ofother disposable absorbent articles include, but are not limited to,absorbent pants, diapers, feminine care products, incontinence products,or the like. The present invention also contemplates other products ordevices unrelated to disposable absorbent articles. For the purposes ofthis description, the term "product" can refer, but is not limited, toany article, device, laminate, composite, or the like. The term"component" can refer, but is not limited, to designated selectedregions, such as edges, corners, sides or the like; structural members,such as elastic strips, absorbent pads, stretchable layers or panels,layers of material, or the like; or a graphic. The term "graphic" canrefer, but is not limited, to any design, pattern, or the like.

A child's disposable training pant can have, by way of example, multipleappearance-related and/or functional components registered withinselected machine-direction (MD) and/or cross-direction (CD) ranges. Theterm "machine-direction" refers to the primary direction of movement ofcontinuously moving layers in the manufacturing process, and the term"cross-direction" refers to a direction transverse to themachine-direction. The described example herein is that of registering agraphic in the machine direction within a designated area of the pant.

Thus, the present invention can provide a child's disposable trainingpant having one or more appearance-related or functional componentsregistered with other components. Examples of components that areappearance-related include, but are not limited to, the registration ofgraphics; highlighting or emphasizing leg and waist openings in order tomake product shaping more evident or visible to the user; highlightingor emphasizing areas of the product to simulate functional componentssuch as elastic leg bands, elastic waistbands, simulated "fly openings"for boys, ruffles for girls; highlighting areas of the product to changethe appearance of the size of the product; registering wetnessindicators, temperature indicators, and the like in the product;registering a back label, or a front label, in the product; andregistering written instructions at a desired location in the product.

Examples of functional components include, but are not limited to, waistelastics, leg elastics, areas of breatheability, fluid repellent areas,fluid wettable areas, adhesives or coatings, encapsulated inks,chemically-sensitive materials, environmentally-sensitive materials,heat-sensitive materials, moisture-sensitive materials, perfumes, odorcontrol agents, inks, fasteners, fluid storage areas, textured orembossed areas, or the like.

The training pant described herein comprises an absorbent pad positionedbetween a liquid impermeable outer cover and a liquid permeable liner.The training pant further includes elastic side panels which are joinedto the outer cover in order to provide elasticity thereto. The liquidimpermeable outer cover can comprise two layers of material suitablyjoined together, in which the innermost layer can be a liquidimpermeable layer and the outermost layer can be a nonwoven layer havingcloth-like texture. In this case, it is the innermost liquid impermeablelayer that has a graphic printed in registration thereon. The registeredgraphic generally includes a visually pleasing design or pattern and iscontrollably registered at a designated area in the product. An exampleof one registered graphic includes a graphic positioned on the frontcenter of the pant, and includes a simulated elastic waistband,simulated elastic leg bands, a simulated "fly opening" for boys,simulated ruffles for girls, or the like. A more detailed description ofthe construction and design of a disposable absorbent training pant isin U.S. Pat. No. 4,940,464 issued Jul. 10, 1990, the contents of whichare incorporated by reference herein.

Described herein is a distinctive process and apparatus for registeringa plurality of distinct and separate components selectively positionedon a continuously moving first layer of material with a respectiveplurality of distinct and separate components selectively positioned ona continuously moving second layer of material. The second layer ofmaterial has the components suitably represented by respective referencemarks, both provided thereon at a uniform repeat length that is shorterthan a machine product repeat length, defined hereafter. The distancebetween two successive reference marks is determined and then used tocalculate a control signal for the current process conditions. When acontrol signal is calculated, the second layer of material is thencontrollably drawn or elongated so that the distance between twosuccessive reference marks substantially equals the selected distance,which in this case is one machine product repeat length; this is termedthe "repeat loop". The second layer is controllably registered to thefirst layer of material so that each reference mark is selectivelyregistered with a respective component; this is termed the "placementloop". The term "reference mark" can refer, but is not limited, tostructure such as waist or leg elastics, adhesive beads, corners oredges of structure, transporting mediums such as conveyor belts, visualmarks, magnetic marks, electrical marks, electromagnetic marks, opticalbrighteners sensitive to ultraviolet radiation, or the like, all ofwhich can be sensed, detected, or otherwise identified by an appropriatedevice. The term "machine product repeat length" refers to a selecteddistance, which in this example is the measured distance betweensuccessive, like components during manufacture. For example, betweensuccessive waist bands, absorbent pads, or the like. Or in other words,the machine product repeat length is the length of one product duringthe manufacturing process. Thus, when a reference mark is registeredwith a component of the first layer, then the component represented bythat reference mark is registered with the component of the first layer.

With regard to the repeat loop, the second layer has the reference marksselectively provided thereon to correspond to a respective plurality ofdistinct and separate components, such as graphics. A first sensorgenerates a signal in response to each reference mark. The distancebetween each newly generated signal and the most recently precedingsignal is suitably measured in units of a drawing or elongatingmechanism, so that the mechanism can be operated to draw or elongate thesecond layer, so that the distance between a subsequent newly generatedsignal and its most recently preceding signal is one machine productrepeat length. Thus, the repeat loop refers to repeatedly duplicating aproduct length between two successive reference marks.

The term "draw", and variations thereof, such as, by way of example,"drawing" and "drawn", generally refers to selectively applying a forceor a pressure against a moving layer of material to controllablyelongate the material.

With regard to the placement loop, a desired registration of a referencemark to a component is performed by comparing and controlling a relateddatum value to a target set point. A "datum value" refers to a measureddistance between a reference mark and a machine-generated constantreference signal. A "target set point" refers to a selected value withinwhich the datum value is maintained.

There is described herein, by way of example, a distinctive process andapparatus for using a preprinted layer of material including a pluralityof distinct and separate graphics thereon, varying the length asnecessary of the layer to coincide with a selected length, and thenapplying and registering it to another layer that includes preassembled,preapplied components, such as absorbent pads, thereby providing amanufacturing process for individual disposable absorbent articleshaving graphics registered thereon at designated areas. The process andapparatus can also be used to apply, during manufacture, other variousfunctional and appearance-related components that have been printed,joined, positioned, or the like, on a layer at a specified location soas to be selectively registered in the final product.

The second layer of material is preprinted with a plurality of separateand distinct graphics. The printed graphics are arranged such that theyultimately will be positioned at the same designated area in eachfinished product. The term "finished" or "final", when used withreference to a product, means that the product has been suitablymanufactured for its intended purpose. The material of which the secondlayer is made has a crystalline nature or property such that it can bepermanently set. The term "permanently set", or variations thereof, suchas, by way of example, "permanently settable", refers to a property ornature that allows or causes the material to hold or maintain adeformation. For example, a permanently settable material moved betweena pair of calendering rolls having a nip dimension less than thethickness of the material will have its thickness reduced or thinned ordrawn to the dimension of the nip, and will thereafter hold the reducedthickness. The length of the drawn material, as well as its widthpossibly, will be increased due to the drawing or thinning action on thematerial's thickness. The material's reduced thickness and increasedlength is firmly fixed or permanently set thereafter, at least forpurposes of and under the conditions of the manufacturing process. Thematerial will not tend to return to its original shape. These types ofmaterials are crystalline in nature, i.e., have crystalline properties,and desirably are highly crystalline in nature. They generally do nothave the properties of amorphous materials. Crystalline materials have aregularly repeating internal arrangement of particles, such as moleculesor atoms. Examples of crystalline materials are plastics such as, by wayof example, oriented polypropylene, oriented polyester, oriented nylon,spunbond fibers, or the like. The more oriented, more crystalline thematerial, the more permanent or fixed will be its set after, forexample, being drawn or thinned. The more crystalline the material, thebetter it holds a selected deformation or set. Desirably, the selecteddeformation or set is firmly fixed and remains so throughout subsequenthandling in a manufacturing process. Examples of deforming or drawing orthinning include, but are not limited to, cold-rolling, calendering,neck stretching, or the like.

The second layer is selectively drawn to controllably elongate it, so asto appropriately coincide the distance between two successive referencemarks to the machine product repeat length and to control a relateddatum value to a target setpoint. This is done in order to register thereference marks to previously processed and preplaced components, suchas, by way of example, absorbent pads. A system of sensors used inconjunction with computer hardware and software inspects for registeredlocation, repeat patterns, and setpoint error. The data received fromthese sensors is used to control the drawing or elongating as necessaryfor desired registration. Adjustments to the second layer are made sothat the preprinted graphics are desirably registered with a respectiveplurality of components. The distance between the preprinted referencemarks is determined with reference to the material of which the secondlayer is comprised, since the material is to be elongated to space thereference marks farther apart in order to coincide with a machineproduct repeat length. If the reference marks are initially spaced tooclose together on the selected material, it may not be possible toincrease their distance apart, by drawing or elongating the material, tocoincide with a machine product repeat length.

These features advantageously affect a layer moving at high speed inorder to register it with another layer. In particular, there isprovided accurate, real time information during the production process,and rapid adjustments to the process to provide the desiredconfiguration and registration of the reference marks and theirassociated components in the final product. The use of the term "layer"can refer, but is not limited, to any type of substrate, such as a wovenweb, nonwoven web, films, laminates, composites, elastomeric materials,or the like. A layer can be liquid and air permeable, permeable to airbut impermeable to liquids, impermeable both to air and liquid, or thelike.

Each of the separate and distinct graphics selectively positioned on thecontinuously moving layer has a reference mark associated therewith.This means that each reference mark is selectively positioned withregard to a respective graphic, so that the reference mark can be sensedand appropriately registered in the product, thereby properlyregistering each graphic in its product. Earlier, a reference mark wasdescribed in terms of specific examples, and in the followingdescription the reference mark is selected as an optical brightener. Areference mark, whether an optical brightener or other means, can beconfigured in any desired size or shape. The reference mark may comprisea generally rectangular region having a machine direction dimension ofabout 19 millimeters and a cross direction dimension of about 37millimeters. Other dimensions optionally may be employed. It is to beunderstood that the various detecting and sensing means described hereinare to be appropriately compatible with the type of associated referencemark that is to be detected or sensed. The term "associated" refers tothe reference mark either being directly on a component that itrepresents, such as a graphic, or being selectively spaced therefrom.The optical brightener is provided to be sensitive to ultravioletradiation. The optical brightener is, for example, capable of absorbingultraviolet radiation and then fluorescing to emit light spectra thatcan be sensed by an appropriate and compatible detector or sensor.Ultraviolet radiation is generally understood to include electromagneticradiation having wave lengths ranging from about 20-400 nanometers.Suitable optical brighteners include, for example, UVITEX OBmanufactured by Ciba-Geigy, and LEUCOPURE EGM manufactured by SandozChemicals Corporation.

Where the reference mark comprises ultraviolet sensitive opticalbrighteners, a suitable detector or sensor is a UV activated detector,such as a SICK detector model LUT 2-6 available from SICK OPTIKELEKTRONIK, INC., a business having offices in St. Paul, Minn.

Other suitable reference marks, as well as sensors, computer devices,motors, and the like are described in U.S. Pat. No. 5,235,515; U.S. Pat.No. 5,359,525; and U.S. Pat. No. 4,837,715; the contents of these threeaforementioned U.S. patents being incorporated by reference herein.

The described process and apparatus utilize several devices, andrepresentative devices include encoders, signal counters, and sensors.An encoder generates a pulse train, which is a selected number of pulsesper revolution of the encoder shaft, for subsequent counting andcontrol. A signal counter receives a generated pulse train from anencoder, and counts the pulses for subsequent query. A sensor senses anoccurrence or interruption in a process and generates a signal inresponse thereto.

Referring now to FIG. 1, there is illustrated a child's disposabletraining pant 10 generally comprising a front panel 12, a back panel 14,a crotch panel 16 interconnecting front and back panels 12, 14, and apair of elastic side panels 18. Each elastic side panel 18 is formedfrom two separate elastic portions (FIG. 2A) and are suitably joinedtogether, such as by ultrasonic bonding, to form a side seam 20. Uponthe construction of side seams 20, a waist opening 22 and leg openings24 are formed. The side seams 20 may be constructed to be manuallytearable in order to allow training pant 10 to be disassembled manuallyby the caregiver, so that it can be easily removed from the child aftera bowel movement. The elastic side panels 18 (FIG. 1) and side seams 20can be provided in any suitable manner. One specific manner of supplyingelastic side panels 18 is described in U.S. Pat. No. 5,224,405 and U.S.Pat. No. 5,104,116, both of which are incorporated by reference herein.The provision of side seams 20 can be accomplished in the mannerdescribed in U.S. Pat. No. 5,046,272, which is incorporated by referenceherein.

Training pant 10 further comprises a front waist elastic 26 suitablyjoined to front panel 12, a back waist elastic 28 suitably joined toback panel 14, leg elastics 30 suitably joined to crotch panel 16, andan absorbent pad 32 (FIG. 4) positioned between a liquid impermeableouter cover or backsheet 34 (FIG. 1) and a liquid permeable liner ortopsheet 36. The basic construction of a training pant is well known inthe art, and one particular construction is that described in U.S. Pat.No. 4,940,464, issued Jul. 10, 1990, the contents of which areincorporated by reference herein. U.S. Pat. No. 4,940,464 also describesvarious materials of which a training pant can be made, and the methodsof constructing the training pant.

As illustrated in FIG. 1, a registered graphic 38 is selectivelypositioned on front panel 12, and in this illustration comprises adesign of a simulated "fly opening 23", typical of a boy's underwear,and a rainbow, sun, clouds, and cars. The registered graphic 38 can beany type of desired pattern, artistic feature, written instructions, orthe like, and is desired to be positioned in the article at a selectedlocation. Naturally, registered graphic 38 comprising a simulated flyopening 23 would be totally unacceptable from an aesthetic and/orfunctional viewpoint if it were located at crotch panel 16 or back panel14.

Referring to FIG. 2, another training pant 40 is illustrated, which canbe typically used for young girls. In this design, a registered graphic42 includes simulated waist ruffles 29, simulated leg ruffles 31, arainbow, sun, clouds, wagon and balloon. Again, any suitable design canbe utilized for a training pant intended for use by young girls, so asto be aesthetically and/or functionally pleasing to them and thecaregiver.

Registered graphic 38 in FIG. 1 or registered graphic 42 in FIG. 2 canbe controllably registered as desired, depending upon the size and shapeof the graphic and that portion of the article upon which the graphic isto be registered. In FIG. 1, graphic 38 is controllably registeredwithin a designated area 39 which, as viewed in FIG. 1, is bounded ordefined by a front waist edge 116, panel seams 21, and a crotch panelline 17. Panel seams 21 are the seams at which the respective elasticside panels 18 are suitably joined to front panel 12 and back panel 14.Again, a more specific description of the construction and manufactureof this design of a training pant 10 is contained in the aforementionedU.S. Pat. No. 4,940,464. The crotch panel line 17 is, for purposes ofexplanation herein, simply the line or boundary formed at the bottom ofcrotch panel 16 as illustrated in FIG. 1. Thus described, designatedarea 39 has four defined boundaries comprising front waist edge 116,panel seams 21, crotch panel line 17, and those portions of leg openings24 extending between a respective panel seam 21 and crotch panel line17. It is not necessary that a designated area 39 be completely definedor bounded by a closed line or closed boundary. For example, in FIG. 1,the designated area 39 could be defined by only front waist edge 116,panel seams 21, which sufficiently define a designated area 39 in whicha graphic 38 can be controllably registered. In this case, the graphic38 can be controllably registered a selected distance from front waistedge 116, and centered between panel seams 21.

Another example of the flexibility in choosing a designated area 39 isillustrated in FIG. 2A, which illustrates the training pant 40 in FIG. 2in a partially disassembled, stretched flat state. This stretched flatstate can be accomplished by taking the finished training pant 40 ofFIG. 2 and manually tearing seams 20 and then laying the pant 40 flatand stretching it sufficiently to remove any gathers or pleating causedby any incorporated elastic members. In FIG. 2A, designated area 39 isdefined or bounded by front waist edge 116, panel seams 21, back waistedge 118, and a pair of leg opening edges 25 extending betweenrespective panel seams 21. Thus, in FIG. 2A, designated area 39 isgenerally rectangular in shape, and registered graphic 42 is registeredwithin and throughout the surface area of designated area 39. Registeredgraphic 42 comprises several component designs, such as simulated legruffles 31 and simulated waist ruffles 29. As viewed in FIG. 2A, legopening edges 25 are linear or straight lines. However, in FIG. 2,simulated leg ruffles 31 provide a perceived curvature or shape totraining pant 40, which is one of the unique features herein.

There is uniquely and advantageously provided a very close tolerance inthe registration of a desired component, such as graphics 38, 42, withinany selected area, such as a designated area 39. With reference to FIG.1, it is apparent that the simulated fly opening 23 of graphic 38 needsto be registered within front panel 12. It would be undesirable to havetraining pant 10 manufactured by a method and/or apparatus that couldnot control the proper registration of simulated fly opening 23,otherwise the simulated fly opening 23 could appear at back panel 14 orcrotch panel 16. The present invention provides a highly controlledregistration of a desired component, such as a graphic 38 or 42, withina desired designated area, such as designated area 39 within a toleranceof about plus or minus 12 millimeters, and within a more particulartolerance between about plus or minus 3 millimeters.

Referring now to FIG. 5, there is schematically shown an apparatus andprocess for assembling in part a plurality of training pants. A supplymeans 44 continuously supplies a continuous, tissue-wrapped absorbent 46to a separating means 48 that separates the continuous, tissue-wrappedabsorbent 46 into a plurality of distinct and separate absorbent pads32. The supply means 44 can be any conventional mechanism for supplyingthe absorbent 46. Generally, a conventional supply means 44 will includea hammermill for forming fluff fibers and, if desired, for providing anenclosure for mixing superabsorbent material with the fluff fibers, andthen depositing the fluff and superabsorbent material on a forming drumhaving a desired absorbent design. The forming drum then deposits theshaped absorbent on a continuously moving tissue material, which isthereafter delivered to a folding board for folding the tissue about theabsorbent. This provides the continuous, tissue-wrapped absorbent 46.The absorbent can include any desired mixture or blend of absorbingmaterials, such as fluff and superabsorbent materials. Suitablesuperabsorbent materials are available from various commercial vendorssuch as Dow Chemical Company, Hoechst-Celanese Corporation and AlliedColloids, Inc. Typically, a superabsorbent material is capable ofabsorbing at least about 15 times its weight in water, and desirablymore than about 25 times its weight in water. A preferred fluff is thatidentified with the trade designation CR1654, available fromKimberly-Clark Corporation, Neenah, Wis., and is a bleached, highlyabsorbent sulfate wood pulp containing primarily soft wood fibers.

A conveyor means 50, which can be any conventional conveyor means wellknown in the art, conveys the absorbent 46 to the separating means 48. Asupply means 52 provides a continuously moving first layer of material54, upon which can be disposed any desired component, such as theseparate and distinct absorbent pads 32 formed by separating means 48.The supply means 52 can be any standard unwind mechanism that generallycomprises a pair of spindles, a festoon assembly, and a dancer roll forproviding first layer 54 at a desired speed and tension. One example ofa standard unwind is a model MB 820, available from Martin AutomaticCorporation of Rockford, Ill. The continuously moving first layer ofmaterial 54 can be any desired material suitable for the particularproduct being assembled. In this description of a training pant 10 (FIG.1), continuously moving first layer 54 is a liquid permeable materialthat will subsequently form or become liquid permeable topsheet 36 (FIG.1). Topsheet 36 can be made of any suitable materials well known in theart, and examples of suitable materials are described in theaforementioned incorporated U.S. patents.

Upon being moved or delivered to separating means 48, the continuous,tissue-wrapped absorbent 46 is cut into the separate and distinctabsorbent pads by a knife roll 56 and an anvil roll 58 comprisingseparating means 48. The knife roll 56 can have any desired number ofblades thereon, and in this example has two blades 60 diametricallydisposed thereon for forming absorbent pads 32. Knife roll 56 is drivenby and mechanically coupled through gearing to anvil roll 58, which isoperatively driven by a main lineshaft 128 (FIG. 6) in any suitablemanner well known in the art. A constant reference means, such as aproximity switch 62, is coupled to anvil roll 58 for generating areference signal for each cut absorbent pad 32. For purposes herein, theseparating means 48 is operated at a substantially constant speed duringthe manufacturing process so that each reference signal generated byproximity switch 62 is considered a machine constant reference signalfor purposes of comparison to other signals hereafter described. Themachine-generated constant reference signal from proximity switch 62 istransmitted to a main control system for further processing as describedhereafter.

The distinct and separate absorbent pads 32 formed by separating means48 are selectively positioned upon the continuously moving first layerof material 54 provided by supply means 52. It is well known in the artto separate and selectively position individually cut absorbent padsonto a continuously moving layer, and any such suitable mechanism can beutilized herein.

A supply means 64, which can be a standard unwind similar to that usedwith reference to the supply means 52, provides a continuously movingsecond layer 66 of material that will subsequently be joined tocontinuously moving first layer 54. Continuously moving second layer 66moves toward a pair of driven rolls 68, 70 that form therebetween acompression nip 72. Drive rolls 68, 70 can be suitably coupled anddriven by any suitable motor, such as those described in the U.S.patents incorporated by reference herein. A suitable compression nipmotor is a HR 2000 brushless AC servo motor available from RelianceElectric Company, of Cleveland, Ohio. As earlier described, the materialof which second layer 66 is made is elongatable by, for example, drawingor compressing, so that it can be lengthened, by way of example, betweenabout 0.5% to about 5.0% of a length, for example, a machine productrepeat length. The continuously moving second layer 66, in thisparticular description, is a liquid impermeable film that willsubsequently form liquid impermeable outer cover 34 (FIG. 1), and suchfilms are available from Edison Plastics Company of South Plainfield,N.J.

It is desired that the compression nip motor 148 (FIG. 6) and its drivesystem, which operates drive rolls 68, 70 is one that is capable ofperforming two types of controllable speed variations, as controlled bythe main control system, which will be described in greater detailhereafter. One speed adjustment or variation is to increase a presentspeed of the rotation to a faster speed of rotation, or to decrease apresent speed of rotation to a slower speed of rotation. This speedadjustment is used for the repeat loop. The other speed adjustment orvariation is a momentary speed adjustment or variation comprising anincremental advance phase move, which is a momentary speed increase ofdrive rolls 68, 70 to provide a measured increased amount of the layerof material, or an incremental retard phase move, which is a momentaryspeed decrease of drive rolls 68, 70 to provide a measured decreasedamount of the layer of material. The term "momentary speed increase"refers to increasing a first speed to a higher second speed for aselected period of time, and then causing the speed to return to thefirst speed, in order to advance the position of the layer and theassociated graphics upstream of the nip by a measured amount. The term"momentary speed decrease" refers to decreasing a first speed to a lowersecond speed for a selected period of time, and then causing the speedto return to the first speed, in order to retard the position of thelayer and the associated graphics upstream of the nip by a measuredamount. This momentary speed adjustment is used for the placement loop.

As a speed increase or decrease is made, for either a repeat loop orplacement loop speed change, the material needs to be controllablyelongated to match the downstream web speed. This prevents the webtension from becoming too high, which will cause a web break, orbecoming too low, which will cause a slack web and ultimately a wrap up.A compression regulation mechanism is used for this controlledelongation. The mechanism consists of a dancer assembly 79 whichincludes a position feedback sensor. When the compression nip 72 speedsup or slows down, the dancer assembly automatically supplies or takes upmaterial by changing position. The associated position feedback signalis used to increase or decrease the pressure on compression nip 72correspondingly increasing or decreasing the elongating effect resultingin the associated advance or retard in the position of layer 66.

The present invention can be utilized to register two continuouslymoving layers together, so that a reference mark and/or productcomponent of one layer is registered with a reference mark and/orproduct component on the second layer. In this particular description, acomponent, such as a registered graphic 38 (FIG. 1) on continuouslymoving second layer 66 (FIG. 5) is brought in registration with acomponent, such as an absorbent pad 32, on continuously moving firstlayer 54. By controllably registering a registered graphic 38 with anabsorbent pad 32, the desired position of registered graphic 38 on afront panel 12 (FIG. 1) of a training pant 10 can be accomplished. Animportant function of a registered graphic 38 on a front panel 12 isthat it visually informs the user of the proper orientation of thetraining pant 10 for donning purposes, thereby permitting the trainingpant to properly function, i.e., absorb waste, among other functions.The continuously moving layer 66 has, by way of example, preprintedthereon a plurality of separate and distinct graphics 38, such that thegraphics 38 can be registered with the separate and distinct absorbentpads 32 on continuously moving layer 54. There is associated with eachgraphic 38 a preprinted reference mark 74, which in this case is anoptical brightener. The graphics 38 and their respective reference marks74 can be provided on layer 66 in any suitable manner well known in theart.

With reference to FIG. 3, there is illustrated a portion of continuouslymoving layer 66 having a plurality of the graphics 38 and referencemarks 74 preprinted or prepositioned thereon. Associated with eachgraphic 38 is a printed waistband 76 with a printed front edge 78 and aprinted back edge 80. Similarly, each reference mark 74 has a referencefront edge 82 and a reference back edge 84. Each reference mark 74 willbe used to properly position an associated graphic 38 with an absorbentpad 32. The reference marks 74 are positioned off graphics 38, but couldbe printed directly on the graphics 38 so as to be within the design ofthe graphics. Furthermore, the reference marks 74 can be eliminated, anda portion of a graphic 38 can be used as the reference mark. Alsodetectable marks or the like could be printed as part of graphics 38 andthereafter used for properly registering the graphics 38. However, forpurposes of explanation and manufacture, reference marks 74 are provideda selected distance apart from respective graphics 38.

In the following description, the continuously moving second layer 66will be described, by way of example, as being joined or laminated toanother third layer 92 (FIG. 5) of material in order to produce atwo-layered laminate that ultimately will form the liquid impermeableouter cover 34 (FIG. 1). The material of which layer 66 is made servesas a liquid impermeable barrier, while the third layer of materialjoined to layer 66 will provide cloth-like texture to the outer cover.The cloth-like layer will be the outermost layer. There is norequirement, however, for the third layer, and in some product designs,the cloth-like layer can be eliminated.

From supply means 64, layer 66 moves through a drawing or elongatingmechanism or means, such as a variable press 65. The variable press 65is adjusted to open or close compression nip 72 formed by drive rolls68, 70 through any suitable control means, such as a hydraulic cylinderarrangement, servo motor arrangement, or the like. One such example is alinear actuator 67 operatively connected by a connecting rod 63 to adriven pressure roll 68 which acts upon driven support roll 70. Thecylindrical outer surfaces of rolls 68, 70 can have any desired surfacefinish or feature such as, by way of example, smooth surfaces, roughenedsurfaces, embossed surfaces, or the like. Rolls 68, 70 can have the sameor different surface finish or feature. The surface finish or featuregenerally will depend on the material being drawn or elongated, variousprocessing parameters, or the like. One of the purposes of variablepress 65 is to apply a force or pressure against layer 66 tocontrollably increase the distance between reference marks 74. This canbe accomplished by controllably moving roll 68 toward roll 70 to adjustthe dimension of compression nip 72 formed between roll 68 and roll 70.As long as compression nip 72 has a gap or dimension less than thethickness of layer 66, layer 66 will be drawn or elongated upon beingpulled or moved therebetween by drive rolls 68, 70. As layer 66 is drawnor elongated, its length is increased, thereby increasing the distancebetween subsequent successive reference marks 74. The drawing orelongating also results in a decrease of the thickness of layer 66. Bycontrolling the movement of driven pressure roll 68 toward or away fromdriven support roll 70, the gap or dimension of compression nip 72 isselectively adjusted, thereby selectively controlling the drawing orelongating of layer 66 and the distance between subsequent successivereference marks 74. This allows the distance between any two subsequentsuccessive reference marks 74 to be controllably adjusted so as tocoincide with a machine product repeat length.

After variable press 65, layer 66 is moved through dancer assembly 79,comprising an idler roll 75, a dancer roll 69, and an idler roll 77.Dancer assembly 79 provides festooning for layer 66 and a positionfeedback signal to be used by linear actuator 67, which adjusts the gapof compression nip 72. A suitable dancer assembly is available fromMartin Automatic Corporation of Rockford, Ill. Layer 66 then movestoward a laminator chill roll 86 and an associated support roll 88,which form therebetween a laminator nip 90. A continuously moving layer92 is provided and driven in any suitable manner to laminator chill roll86. An adhesive applicator 94 applies a desired pattern of a suitableadhesive to the continuously moving layer 92. In this particularembodiment, layer 92 is a nonwoven web, such as a spunbond polypropyleneweb having a basis weight of about 20 grams per square meter (gsm). Theadhesive applicator 94 can be any suitable applicator well known in theart that can provide or apply the desired pattern of adhesive. Theadhesive used can be any suitable adhesive that is compatible to layers66 and 92, in order to ensure their proper lamination together.Continuously moving layer 92 can be provided by a supply means (notshown) similar to supply means 52 and 64. Laminator chill roll 86 isdriven by the lineshaft 128 (FIG. 6) and assists in moving the layers inthe process. The laminator chill roll 86 also serves to cool theadhesive applied by adhesive applicator 94 for processing purposes,thereby preventing adhesives from bleeding through the layers 66 or 92.Again, if desired, the laminating or joining of layer 92 to layer 66 canbe eliminated.

Once layers 66, 92 are laminated and pass through laminator nip 90, theyare continuously moved to a construction chill roll 96, and have anadhesive applied to the outermost surface of layer 66. Constructionchill roll 96 can also be driven by lineshaft 128. The adhesive appliedby adhesive applicator 98 will ultimately join layers 66, 92 tocontinuously moving first layer 54. Thus, adhesive applicator 98 isdesigned to apply the appropriate adhesive pattern and amount ofadhesive to ensure the desired joining of the layers 66, 92, and 54. Theconstruction adhesive applicator 98, as well as the adhesive appliedthereby, can be any type of applicator suitable for the desired adhesivepattern, and appropriate and compatible for the materials to be joined.

From construction chill roll 96, the laminated layers 66, 92 are thensuperimposed over continuously moving layer 54, and together the layerspass through a product tacker 100 comprising a drive roll 102 driven bylineshaft 128 (FIG. 6) and a rubber-coated idler roll 104. Tacker 100compresses the layers together in order to cause the applied adhesive tojoin layers 66, 92 to continuously moving layer 54, thereby forming acontinuously moving composite layer 93 as illustrated in FIGS. 4 and 5.

Continuing to refer to FIG. 5, a first sensing means, such as a sensor106, is suitably positioned between dancer assembly 79 and laminator nip90 for detecting and generating a signal in response to each referencemark 74. Since the reference marks 74 are ultraviolet-sensitive opticalbrighteners, a suitable sensor is a SICK detector model LUT 2-6available from SICK OPTIK ELEKTRONIK, Inc., having a business office inSt. Paul, Minn.

Positioned downstream of product tacker 100 are second and third sensingmeans, such as a sensor 108 and a photoeye 110. The term "downstream"refers to a left-to-right direction as viewed in FIG. 5, and is also themachine direction for the process. Sensor 108 can be the same type ofultraviolet detector as sensor 106. The photoeye 110 is desirably aBanner RSBF scanner block, RPBT wiring base, IR 2.53S fiber-optic pairdevice, available from Banner Engineering, Corp. of Minneapolis, Minn.Photoeye 110 is designed to optically detect a product component, suchas absorbent pad 32, and to generate an electrical signal in responsethereto. In this particular description, both sensors 106 and 108 aredesigned to detect and generate a signal in response to a reference mark74, and photoeye 110 is designed to detect and generate a signal inresponse to an absorbent pad 32. If desired, photoeye 110 can senseother components, such as waist elastics, leg elastics, fastening tapesutilized in diapers, or the like. A reference mark also can beassociated with each absorbent pad 32 in the same manner that areference mark 74 is associated with a graphic 38; and in this case, thepad photoeye 110 can be replaced with a sensor similar to sensors 106,108. Similarly, sensors 106, 108 can be replaced with other sensors,similar to photoeye 110, in order to optically detect a productcomponent or other structure in order to generate an appropriate signal.

With reference to FIG. 4, there is illustrated a continuously movingcomposite layer 93 comprising layers 66, 92, and 54 (FIG. 5) after theyhave been joined together by product tacker 100. Each printed waistband76 will ultimately be cut along a respective cut line 120 in order toform individual products. In FIG. 4, once cut lines 120 have beenseparated, a front waist edge 116 and a back waist edge 118 are formedfor each assembled product. One of the important features in FIG. 4 isthe relative placement of a graphic 38 with respect to each product thatwill eventually be formed. Each graphic 38 is located in the front panel12 (FIG. 1) and is located in the same position relative to an absorbentpad front edge 112 (FIG. 4). Naturally, other marks or productcomponents can be in registration with other different reference marksor product components. For example, a simulated waist ruffle 29 (FIG. 2)can be registered relative to a waist opening, or leg elastics, such asleg elastics 30 (FIG. 1), can be desirably registered in relation to anabsorbent pad, such as absorbent pad 32 (FIG. 4).

Referring to FIG. 6, there is schematically illustrated a main controlsystem with a mechanical side 122. The main control system comprises amain registration control system 124 that receives various generatedsignals, processes them in accordance with programmed instructions, andgenerates output signals to a main drive control system 126. The maindrive control system 126 receives the signals from the main registrationcontrol system 124, and in response thereto controls, as necessary, thespeed of drive rolls 68, 70. Linear actuator 67 of variable press 65 iscontrolled in response to the position of dancer roll 69 throughsuitable means well known in the art, separately from the mainregistration control system 124.

Main drive control system 126 can be designed to operate or controlother areas or mechanisms.

Mechanical side 122 comprises a main lineshaft 128 that directly drivesselected mechanisms or, through a system of gears and other couplingdevices, both electrical and mechanical, indirectly drives othermechanisms. Lineshaft 128 is driven at a constant speed, by any suitablemeans known in the art, and those mechanisms driven by lineshaft 128 arealso driven at a constant speed, which may or may not be the same speedas that of lineshaft 128. Specifically, a compression nip gearingencoder 130 and a lineshaft registration encoder 132 are operativelycoupled to lineshaft 128. Examples of encoders include anH25D-SS-2500-ABZC-8830-LED-SM18 (which can be used as encoder 130),available from BEI Motor System, Co. of Carlsbad, Calif., and a63-P-MEF-1000-T-0-00 (which can be encoder 132) available from DynaparCorp. of Gurnee, Ill. Compression nip gearing encoder 130 is operativelycoupled to lineshaft 128 to rotate at a constant speed, such that fourrevolutions of encoder 130 represents one machine product repeat length.

The main registration control system 124 comprises hardware and/orpreprogrammed software instructions, and can be represented, withreference to FIG. 6, as comprising an input acquisition system 134, agear ratio control 136, a relative position 138, an automatic set pointgeneration 140, a difference block 142, and a placement control 144. Themain registration control system 124 includes a computer, which cancomprise, for example, a VME-based microprocessor, such as aSYS68K/CPU-40B/4-01 available from Force Computers, Inc. of Campbell,Calif.

As illustrated in FIG. 6, input acquisition system 134 can be designedto receive the following six generated signals: (i) a signal from amotor encoder 146 operatively coupled to a motor 148 that drives driverolls 68, 70, (ii) a signal from sensor 106 (FIG. 5), (iii) a signalfrom proximity switch 62 (FIG. 5), (iv) a signal from lineshaftregistration encoder 132, (v) a signal from sensor 108 (FIG. 5), and(vi) a signal from photoeye 110 (FIG. 5). Input acquisition system 134receives and counts the pulses generated by motor encoder 146 andlineshaft registration encoder 132, and receives signals from sensors106, 108, proximity switch 62, and photoeye 110. Referencing theaccumulated counts of encoder 146 and the accumulated counts of encoder132, input acquisition system 134 performs preprogrammed instructionsthat are specific to the respective received signals, and stores theresults of the instructions.

In a similar manner, input acquisition system 134 can be designed toreceive signals from motor encoders or the like operatively coupled tomotors that can drive other mechanisms, perform preprogrammedinstructions specific to the received signals, and store the results ofthe instructions.

For the gear ratio control 136, a signal counter in input acquisitionsystem 134 counts the pulses from motor encoder 146, and receivessignals from sensor 106 in response to each reference mark 74 (FIG. 5).The input acquisition system 134 then measures the counted pulsesrepresenting a distance between every two successive reference marks 74,and performs a running average of those measured counts. The term"running average" refers to averaging the same number of data; forexample, for each newly received datum input, the oldest datum isremoved from the averaging calculation. The averaging of the countsbetween two successive reference marks 74 creates an average measurementupon which the next gear ratio value will be derived by gear ratiocontrol 136, as opposed to basing a control decision on the measurementfrom just one pair of reference marks 74. This averaging "smoothes out"the measurements, and is necessitated due to the variability of theapparatus and process. The number of measurements to average iscontrollable, and is set or determined by providing an appropriateinstruction via manual input in any suitable manner well known in theart. In conjunction with performing a running average of the measuredcounts, the input acquisition system 134 performs a filtering function,which is preprogrammed, to filter out signal anomalies. Examples of suchsignal anomalies include a dirty photoeye, missing or extra referencemarks 74, movement or weaving of the layers, measuring the countsoutside a preprogrammed range for averaging purposes, known inaccuratedata due to registration control events, or the like.

For the relative position 138, the input acquisition system 134 countsthe pulses received from lineshaft registration encoder 132, andreceives signals generated by sensor 106 and proximity switch 62. Inputacquisition system 134 then determines and records the currentaccumulated number of pulses upon receiving a signal from sensor 106,and determines and records the current accumulated number of pulses uponreceiving a signal from proximity switch 62.

For the automatic set point generation 140, input acquisition system 134counts the pulses received from lineshaft registration encoder 132, andreceives the signals generated by sensor 108 and photoeye 110. It thendetermines and records the current accumulated number of pulses uponreceiving a signal from sensor 108, and determines and records thecurrent accumulated number of pulses upon receiving a signal fromphotoeye 110. Thereafter, input acquisition system 134 calculates thedifference between the current accumulated number of pulses from onesignal of sensor 108 and the current accumulated number of pulses froman associated signal of photoeye 110; the "associated signal" refers tothe signal generated by photoeye 110 (FIG. 5), with the signal fromsensor 108, for each machine product repeat length. With thesecalculated differences, input acquisition system 134 performs a runningaverage and standard deviation for those differences.

The various calculations and functions performed by input acquisitionsystem 134 are utilized by other portions of main registration controlsystem 124 in order to generate commands to main drive control system126 (FIG. 6). Main drive control system 126 generally comprises at leastone logic/control processor 150, at least one electronic gear box 152,and at least one motor controller 154. The main drive control system 126includes a computer, which can comprise, for example, a RelianceDistributed Control System made by Reliance Electric, Co. TheDistributed Control System includes a Reliance Electric AutomaxProcessor and associated hardware. Each electronic gear box 152 (FIGS.6-7) comprises a 2-axis card that is part of the Distributed ControlSystem unit and is used to control the position of its respective motor,such as motor 148.

The gear ratio control 136 queries the input acquisition system 134every 20 products, i.e., every 20 machine product repeat lengths, forthe current running average of measured counts representing a distancebetween successive reference marks 74 (FIG. 5), which is the repeatvalue. The number of product lengths determining a query from gear ratiocontrol 136 is adjustable, and can be changed manually by the operator.After determining the repeat value, gear ratio control 136 performs agear ratio calculation in accordance with preprogrammed instructions todetermine a new gear ratio value, if necessary. That new gear ratiovalue is then transmitted to the logic/control processor 150 of maindrive control system 126. The gear ratio value is calculated by dividingthe repeat value by the number of encoder counts from the compressionnip gearing encoder 130 (FIG. 6) that occur in one machine productrepeat length. The purpose of this is to accommodate the repeat ofreference marks without comparing to a target value.

The relative position 138 of main registration control system 124queries input acquisition system 134 for the current accumulated numberof pulses relative to sensor 106, and the current accumulated number ofpulses relative to proximity switch 62. Relative position 138 thendetermines the difference between the two current accumulated number ofpulses in order to calculate a relative position of a reference mark 74(FIG. 5) to the associated proximity switch signal for that specificquery for each machine product repeat length. The relative position 138then generates and transmits to difference block 142 a relative positionvalue.

The automatic set point generation 140 queries the input acquisitionsystem 134 for each machine product repeat length representing a singleproduct. The occurrence of each product, or machine product repeatlength, is determined from the lineshaft registration encoder 132, inwhich two revolutions of lineshaft registration encoder 132 isequivalent to one product length. In this particular example, tworevolutions of lineshaft registration encoder 132 is 2,000 counts. Theinput acquisition system 134 responds to each query from automatic setpoint generation 140 with the current running average and standarddeviation of the difference calculated between the current accumulatednumber of pulses for one signal of sensor 108 and the currentaccumulated number of pulses from an associated signal from pad photoeye110 for each product; the current running average of this calculation isthe actual position value. The automatic set point generation 140 thencompares a standard deviation with a preset limit, which has beenmanually entered, and if the standard deviation is outside the presetlimit, the automatic set point generation 140 will ignore that datum andnot determine a new set point since the standard deviation data isconsidered too variable to make an accurate set point adjustment. If thestandard deviation is within the preset limit, the automatic set pointgeneration 140 will then determine the difference between the actualposition value and a manually entered target value, which is the desiredactual position value. If the new calculated difference is determined,by automatic set point generation 140, to be within a prescribed range,no further action or calculation will be made. However, if thedifference is outside the prescribed range, the automatic set pointgeneration 140 will determine a new control set point. This new controlset point is derived by adding to the current set point the differencebetween the target value and actual position value.

Once every machine product repeat length, a difference block 142determines the difference between the current control set point valuefrom automatic set point generation 140 and the associated relativeposition value from relative position 138, which is the placement error.The difference block 142 transmits this placement error, in lineshaftencoder counts, to placement control 144. The placement control 144compares the placement error to a tolerance band 170 (FIG. 8), whichdefines an acceptable deviation of the relative position value about thecurrent control set point. The tolerance band 170 remains constant aboutthe control set point, but the control set point can vary as calculatedby automatic set point generation 140. As a result, while the positioncontrol of the reference marks occurs at the nip, the set point for thisposition control is accurately derived from the signals generated bysensor 108 and photoeye 110.

With reference to FIG. 8, there is illustrated one derived set point 168having a prescribed tolerance band 170. For purposes of explanation, thecontrol set point 168 has a value of 1,000 counts, and the toleranceband 170 represents a deviation of plus or minus 12 counts. Each of thedatum points 172, 174, 176, 178, 180 and 182, represents one product'srelative position value as calculated by relative position 138. Waveform156 represents signals generated by proximity switch 62, and waveform158 represents signals generated by sensor 106. If a placement errorvalue remains within tolerance band 170, no placement command will begenerated. However, if a placement error value is outside tolerance band170, then placement control 144 will generate a placement command. Theplacement command is directly proportional to the size of the differencerepresented by the value from difference block 142 and calls for ameasured advance or retard in the position of layer 66. The generatedplacement command is then transmitted to the logic/control processor 150of main drive control system 126. FIG. 8 illustrates an example of howplacement control 144 (FIG. 6) compares each datum point 172-182 to acurrent control set point in order to generate a placement error. Theplacement error for each datum point is compared to tolerance band 170to determine if a placement command should be generated. In the example,point 176 is the only datum point where the placement error fallsoutside the tolerance band 170, which causes a placement command to begenerated, thereby causing a following datum point to fall within thetolerance band 170.

The logic/control processor 150 (FIGS. 6 and 7) of main drive controlsystem 126 searches for and receives new commands from main registrationcontrol system 124. Specifically, processor 150 searches for andreceives gear ratio commands and placement commands from mainregistration control system 124. For each gear ratio value updatecommand, processor 150 transmits a command in accordance withpreprogrammed instructions to electronic gear box 152 to modify thevalue used in a gear ratio block 208 (FIG. 7). For each placementcommand received from placement control 144, processor 150 transmits aplacement command in accordance with preprogrammed instructions toelectronic gear box 152.

As a speed increase or decrease is made, for either a repeat loop orplacement loop speed change, the material needs to be controllablyelongated to match the downstream web speed. This prevents the webtension from becoming too high, which will cause a web break, orbecoming too low, which will cause a slack web and ultimately a wrap up.A compression regulation mechanism is used for this controlledelongation. The mechanism consists of a dancer assembly 79 whichincludes a position feedback sensor. When the compression nip 72 speedsup or slows down, the dancer assembly automatically supplies or takes upmaterial by changing position. The associated position feedback signalis used to increase or decrease the pressure on compression nip 72correspondingly increasing or decreasing the elongating effect resultingin the associated advance or retard in the position of layer 66.

Upon receiving a placement or repeat command from main registrationcontrol system 124, main drive control system 126 will executeassociated speed changes on drive rolls 68, 70 (FIG. 5). When a speedchange is executed on drive rolls 68, 70, the material needs to becontrollably elongated to match the downstream web speed. For example,when the speed of drive rolls 68, 70 increases, the dancer assembly 79automatically takes up excess material by changing position of dancerroll 69. The corresponding position feedback signal is used by thecontroller for linear actuator 67 to increase the gap or dimension ofcompression nip 72. Through this gap or dimension increase, layer 66 iselongated less, thereby returning dancer roll 69 to its normal operatingposition. When the speed of drive rolls 68, 70 decreases, the dancerassembly 79 automatically supplies additional material by changingposition of dancer roll 69. This corresponding position feedback signalis used by the controller for linear actuator 67 to decrease the gap ordimension of compression nip 72. Through this gap or dimension decrease,layer 66 is elongated more, thereby returning dancer roll 69 to itsnormal operating position. These changes are made through linearactuator 67 which drives driven pressure roll 68 through connecting rod63, toward or away from driven support roll 70 to controllably adjustthe gap or dimension of compression nip 72. This regulated gap in turncontrols the amount of drawing or elongating of layer 66 to compensatefor differences in speed between compression nip 72 and laminating nip90.

Referring to FIG. 7, electronic gear box 152 can comprise a gear ratioblock 208, a difference block 210, a speed regulator 212, and anincremental move block 214. The gear ratio block 208 receives a gearratio value from logic/control processor 150 (FIG. 6), and receives apulse train from the compression nip gearing encoder 130. Gear ratioblock 208 scales the pulse train from gearing encoder 130 and appliesthe gear ratio value to it in order to generate a reference signal todifference block 210. Difference block 210 receives both the referencesignal from gear ratio block 208, and also receives a feed back signalfrom motor encoder 146, which communicates the current speed of motor148. The difference block 210 determines the difference between thesignals and generates a command signal to a speed regulator 212, whichgenerates a speed reference signal to motor controller 154. Thus, theelectronic gear box 152 precisely links the speed of the compression nipdrive motor 148 to the speed of the lineshaft 128 through anelectronically changeable gear ratio. This effectively synchronizes thespeed of the nip motor 148 to the lineshaft 128 and allows frequentchanges to the gear ratio, and thus the speed of motor 148. Thesechanges in speed of motor 148, and thus drive rolls 68, 70, aredesirable to accommodate the registration of layer 66.

With reference to FIGS. 6-7, electronic gear box 152 also receives aplacement value from logic/control processor 150, and this placementvalue is received by incremental move block 214. Incremental move block214 performs a "one time" move to appropriately change the referencesignal by a measured amount of compression nip motor encoder counts,thereby calculating an exact one time increase or decrease in the amountof the layer of material being supplied by the nip motor 148. This canbe done by relating the number of encoder counts of the motor encoder146 to an actual amount of the layer of material supplied at compressionnip 72 (FIG. 5). In response to the placement command, an incrementalmove signal is generated and temporarily added to difference block 210,which increments or decrements, the reference signal received from gearratio block 208, thereby resulting in a momentary change in the speedcommand signal sent to the speed regulator 212. Motor controller 154receives the speed command signal from electronic gear box 152 (FIG. 6)and varies the speed of motor 148, which is represented by the motorencoder pulse train, in response thereto.

As described, the desired registration of graphic 38 (FIG. 1) or graphic42 (FIG. 2) in respective training pants 10, 40 can be accomplished. Byselectively controlling the distance between successive reference marks74 (FIG. 5), each mark 74 can be desirably registered with an associatedcomponent, such as an absorbent pad 32. Controlling the distance betweenreference marks 74 to a selected distance, such as machine productrepeat length, accommodates or corrects for variations or other types ofanomalies that may be present in the apparatus or process. Bycontrollably adjusting the speed and the gap of compression nip 72 andthe resulting elongation of continuously moving second layer 66, layer66 is appropriately registered with continuously moving first layer 54,thereby ensuring proper registration of a desired component, such as agraphic 38, to another component, such as a front panel 12 (FIG. 1).

While this invention has been described as having a preferredembodiment, it will be understood that it is capable of furthermodifications. It is therefore intended to cover any variations,equivalents, uses, or adaptations of the invention following the generalprinciples thereof, and including such departures from the presentdisclosure as come or may come within known or customary practice in theart to which this invention pertains and fall within the limits of theappended claims.

What is claimed is:
 1. A process for controllably registering aplurality of components of a continuously moving first layer with aplurality of components on a continuously moving second layer,comprising the steps of:providing a continuously moving first layerincluding a plurality of components being spaced apart a selectedlength, providing a continuously moving second layer comprising apermanently settable material and including a plurality of componentsbeing spaced apart a length less than the selected length, representingthe components of the continuously moving second layer with a respectiveplurality of reference marks, sensing each of the reference marks andgenerating a reference mark signal in response thereto, measuring thedistance between two successive reference mark signals and generating arepeat corrective control signal in accordance with preprogrammedinstructions, drawing the continuously moving second layer to adjust thedistance between two successive reference marks in response to agenerated repeat corrective control signal, superimposing thecontinuously moving first layer and the continuously moving second layertogether, sensing a reference mark of the continuously moving secondlayer and its corresponding component of the continuously moving firstlayer, and generating a placement corrective control signal inaccordance with preprogrammed instructions, and adjusting the speed ofthe continuously moving second layer in response to a generatedplacement corrective control signal to controllably register a referencemark on the continuously moving second layer with its correspondingcomponent on the continuously moving first layer.
 2. The process ofclaim 1 wherein the step of drawing adjusts the distance between twosuccessive reference marks to the selected length.
 3. The process ofclaim 2 wherein the step of drawing includes thinning the second layerof material.
 4. The process of claim 3 wherein the selected distance isa machine product repeat length.
 5. A process for controllablyregistering a plurality of reference marks of a continuously movingfirst layer with a plurality of corresponding reference marks of acontinuously moving second layer, comprising the steps of:providing acontinuously moving first layer including a plurality of reference marksbeing spaced apart a selected length, providing a continuously movingsecond layer comprising a permanently settable material, and including aplurality of corresponding reference marks being spaced apart a lengthless than the selected length, sensing each of the reference marks ofthe continuously moving second layer and generating a reference marksignal in response thereto, measuring the distance between twosuccessive reference mark signals and generating a repeat correctivecontrol signal in accordance with preprogrammed instructions, drawingthe continuously moving second layer to adjust the length in response toa generated repeat corrective control signal, superimposing thecontinuously moving first layer and second layer together, sensing areference mark of the continuously moving second layer and itscorresponding reference mark of the continuously moving first layer andgenerating a placement corrective control signal in accordance withpreprogrammed instructions, and adjusting the speed of the continuouslymoving second layer in response to a generated placement correctivecontrol signal to controllably register a reference mark of thecontinuously moving second layer with its corresponding reference markon the continuously moving first layer.
 6. The process of claim 5wherein the step of drawing adjusts the distance between two successivereference marks to the selective distance.
 7. The process of claim 6wherein the step of drawing includes thinning the second layer ofmaterial.
 8. The process of claim 6 wherein the second layer is liquidimpermeable.
 9. The process of claim 5 wherein the selected distance isa machine product repeat length.
 10. An apparatus for controllablyregistering a plurality of components of a continuously moving firstlayer with a plurality of components on a continuously moving secondlayer, comprising:means for providing a continuously moving first layerincluding a plurality of components being spaced apart a selectedlength, means for providing a continuously moving second layercomprising a permanently settable material, and including a plurality ofcomponents being represented with a respective plurality of referencemarks being spaced apart a length less than the selected length, meansfor sensing each of the reference marks and means for generating areference mark signal in response thereto, means for measuring thedistance between two successive reference mark signals and means forgenerating a repeat corrective control signal in accordance withpreprogrammed instructions, means for drawing the continuously movingsecond layer to adjust the distance between two successive referencemarks in response to a generated repeat corrective control signal, meansfor superimposing the continuously moving first layer and thecontinuously moving second layer together, means for sensing a referencemark of the continuously moving second layer and its correspondingcomponent of the continuously moving first layer, and means forgenerating a placement corrective control signal in accordance withpreprogrammed instructions, and means for adjusting the speed of thecontinuously moving second layer in response to a generated placementcorrective control signal to controllably register a reference mark onthe continuously moving second layer with its corresponding component onthe continuously moving first layer.
 11. The apparatus of claim 10wherein the means for drawing adjusts the distance between twosuccessive reference marks to the selected distance.
 12. The apparatusof claim 11 wherein the means for drawing thins the second layer ofmaterial.
 13. An apparatus for controllably registering a plurality ofreference marks of a continuously moving first layer with a plurality ofcorresponding reference marks of a continuously moving second layer,comprising:means for providing a continuously moving first layerincluding a plurality of reference marks being spaced apart a selecteddistance, means for providing a continuously moving second layercomprising a permanently settable material, and including a plurality ofcorresponding reference marks being spaced apart a length less than theselected length, means for sensing each of the reference marks of thecontinuously moving second layer and means for generating a referencemark signal in response thereto, means for measuring the distancebetween two successive reference mark signals and means for generating arepeat corrective control signal in accordance with preprogrammedinstructions, means for drawing the continuously moving second layer toadjust the length in response to a generated repeat corrective controlsignal, means for superimposing the continuously moving first layer andsecond layer together, means for sensing a reference mark of thecontinuously moving second layer and its corresponding reference mark ofthe continuously moving first layer and means for generating a placementcorrective control signal in accordance with preprogrammed instructions,and means for adjusting the speed of the continuously moving secondlayer in response to a generated placement corrective control signal tocontrollably register a reference mark of the continuously moving secondlayer with its corresponding reference mark on the continuously movingfirst layer.
 14. The apparatus of claim 13 wherein the means for drawingadjusts the distance between two successive reference marks to theselected length.
 15. The apparatus of claim 14 wherein the means fordrawing thins the second layer of material.
 16. The apparatus of claim14 wherein the selected distance is a machine product repeat length.